Electro-optical modulators such as electro-refractive modulators and electro-absorptive modulators modulate the phase or amplitude of an optical signal. A voltage or current controls a material's refractive index in an electro-refractive modulator to modulate the phase or optical absorption of an electro-absorptive modulator to modulate the amplitude of light. Because voltage and current need to be applied to the electro-optical modulators, the electro-optical modulators consume electrical energy due to capacitive load and resistive dissipation. Also, to hold the optical output state to a high or low requires that the voltage or current be sustained, and therefore, the electro-optical modulator tends to consume power even when not modulating.